This Caterpillar is initially just pale greenish-yellow.
As it develops, it gets pairs of black warts along its back and sides.
In later instars these are joined by black lines running along the body.
The caterpillar feeds on:

The pupa is often yellow with black-edged spikes.
It has a upcurved spike on the head, a pair of sideways spikes on the thorax.
There are a pair of black warts along the body on each segment.
The pupa is held by cremaster and girdle on the top or underneath a leaf.

The upper surfaces of the forewings of the adult butterflies
are grey fading to white toward the margins,
with a black apex
containing white spots.
The hindwings have irregular black margins
fading to white at the
bases.